Section 10: Circulation and Gas Exchange

diffusion of gasses and nutrients between environment and body cells.

describe gas and nutrient exchange in a GVC (simple form)

mouth opens into cavity made of radial canals leading to and from a circular canals

simple form GVC anatomy:

Cillia circulate fluid through the canals

how is fluid circulated in GVC simple form

diffusion of gasses and nutrients between environment and cells of the body.

descvribe nutrients and gas exchange in complex form GVC

mouth and pharynx open into a highly branched cavity

complex form GVC anatomy

1. larger body size

2. complex body plans

3. higher metabolic rates

needs for a circulatory system:

1. vessels

2. pumping mechanism

circulatory system has these mechanisms: [2]

1. specialized tissues for digestion

2. more complex cell-cell communication (Hormones)

circulatory systems evolved along with: [2]

hemolymph

Fluid in open circulatory system

sinuses (spaces surrounding organisms

in open circulatory system, heart pumps hemolymph into:

happens in sinuses

chemical exchange in open circulatory system happens in:

draws hemolymph back into the heart

what happens when heart relaxes in open circulatory system

blood

fluid in closed circulatory system

1. vessels

2. heart

in closed circulatory system blood is contained within [2]

1. blood and interstitial fluid

2. interstitial fluid and body cells

in closed circulatory systen chemical exchanges happen between: [2]

through branched system of blood vessels in one direction

in closed circulatory system, blood travels how?

artery

carries blood away from the heart

arterioles

branches of the artery within organs

capillaries

microscopic blood vessels

venules

branches of veins within organs

veins

carries blood back to the heart

atrium

ventricle

heart chambers [2]

1. single

2. double

2 main types of vertebrate circulatory systems

1. pulmocutaneous

2. pulmonary (incomplete septum)

3. pulmonary (complete septum)

three types of double circulation

1. systemic: heart and rest of body

2. pulmonary: heart and gas exchange surface

two circuits in double circulation

one circuit from ehart to gas exchange surface, then abck to the heart

describe single circulation

one atrium, one ventricle.

heart in single circulation

Fish

organism with single circulation

double circulation, heart has two separate atria and a ridge in the ventricle that partially separates oxygen rich/poor blood

describe pulmocutaneous circuit

3: two atria one ventricle

chambers in pulmocutenous heart

double circulation, heart has two searate atria and an incomplete septum in the ventricle to partially separate oxygen rich and poor blood

describe pulmonary circuit (incomplete setup)

double circulation, heart has two separate atria and two separate ventricles

describe complete pulmonary circuit:

much thicker in ventricles

wall thickness in ventricles vs arteries

atrioventricular valves

valves between atria and ventricles

semilunar valves

valves between ventricles and blood vessels

prevention of backflow

function of valves in heart

blood recoiling against AV valve

“lub” sound is caused by what

vibration caused by closing of semilunar valves

“dub” sound is caused by

Heart murmur

when blood squirts backwards through a defective valve

amount of blood pumped by each ventricle per minute

cardiac output

heart rate

rate of contraction of heart per minute

stroke volume

amount of blood pumped by a ventricle in a single contraction

1. both valves are relaxed, blood flows into heart

2. contraction forces all blood into ventricels

3. atria relaxes, ventricles contract

4. blood pumps into large arteries

Cardiac cycle:

1. pulmonary artery

2. aorta

large arteries: [2]

SA node

pacemaker node in heart

ECG (or EKG) electrocardiogram

measures electrical impulses produced by the SA and AV node

AV node

signals are delayed by this node

bundle branches

these pass signals at heart apex

Purkinje fibres

these spread signals throughout ventricles

gives walls elasticity

function of thick connective tissue in arteries

endothelium (single layer of flattened cells)

lines arteries and veins

1. aid in support and contraction

function of smooth muscle in arteries and veins

Unidirectional blood flow at low pressure

valves in veins maintain what?

exchange of materials between blood and interstitial fluid

blood moves slower in capillaries, allowing for:

surface area is much bigger

why does pressure drop in capillaries

cuff reaches a pressure just below the pressure in the artery, the sound of blood flowing can be heard

describe systolic pressure:

the blood flows freely and the sound disappears.

describe diastolic blood pressure:

1. smooth muscle contraction in arteriole

2. precapillary sphincters

how is blood flow regulated in capillaries [2]

1. endocytosis and exocytosis of endothelium

2. diffusion

3. pores

movement of fluids between capillaries and surrounding tissues is via: [3]

blood pressure

movement OUT of capillaries is via:

proteins

movement INTO capillaries is via

1. plasma (55%)

2. cellular elements (45%)

two components of human blood

serum

plasma from which clotting factors have been removed

erythrocytes (RBC)

most numerous cellular element

5

how many types of leukocytes

platelets

pinched off cytoplasmic fragments of bone marrow cells

1. no nuclei, more room for hemoglobin

2. lacks mitochondria

erythrocyte anatomy:

Hemoglobin

iron-containing protein that transports O2

1. neutrophils

2. basophils

3. esosinophils

4. monocytes

5. lymphocytes

5 types of leukocytes:

fight infection

main function of leukocytes

1. in interstitial fluid and the lymphatic system

leukocytes can be found where?

aids in blood clotting

platelet function

1. plasma

2. damaged cells

3. platelets

clotting factors from: [3]

damaged endothelium exposes conenctive tissue in the vessal wall to blood. Platelets in the blood attach to collagen fibresin conenctive tissue, makes nearby platelets sticky

what happens when you get a cut on a blood cell level?

plug

platelets form this to prevent blood loss

fibrin threads, forms fibrin clot.

in larger breaks the platelet plug is reinforced by:

fibrinogen

protein that circulates in the blood and is an inactive form of coagulant. when there is a cut, platelets release a clotting factor.

enzymatic cascade

this happens when clotting factors are released, leads to formation of thrombin

thrombin

enzyme that converts fibrinogen to fibrin

clot

fibrin aggregates into threads to form a:

mitochondria

where does respiration happen

Respiration

cellular process referring to the energy transformation of sugars to ATP

gas exchange

uptake of molecular oxygen from the environment and disharge of CO2 to the environment

1. nostrils. tracheal lungs

2. gills

gas exchange happens where: [2]

Partial pressure

pressure exerted by a gas or mixture of gasses

higher partial pressure to lower partial pressure

gasses always diffuse from regions of:

equal

when in equilibrium, the partial pressure of gasses in air is ______ to that in water

gasses are less soluble in water than in air (e.g., oxygen is more difficult to extrac from water than air)

how do concentrations of gasses differ in water and air?

plasma membrane, respiratory surfaces must be moist

cells that carry out gas exchange have this that must be in contact with solution

diffusion

gas exchange always takes place via

1. area is large

2. path is short

diffusion is fastest when: [2]

large and thin

because respiration is fastest when path is short and area is large, resporatory surfaces tend to be…

Gills

out-foldings of the surface of the body suspended in water.

Ventillation

movement of gills in water

partial pressure gradients necessary for gas exchange

ventillation of gills maintains…

lungs

infoldings of the body, gas exchange on the surface

lungs and the rest of the body

the circulatory system bridges the gap etween:

filters particles

samples odors

warm and humidify air

nose (hair) function

larynx

contains muscular bands called vocal cords